Tweezers.



UNITED STATES PATENT OFFICE.

FRANK R. CUNNINGHAM. OF MEIDFORD, MASSACHUSETTS, ASSIGNOR, BY AS- SIGNMENTS. TO KENDRICK AND DAVIS COMPANY, OF LEBANON, NEW HAMPSHIRE,

A CRPORATION OF NEW HAMPSHIRE.

'rwnnznns Specication o'f Letters Patent.

Patented Nov. L 1911.

Application filed Octobel` 23, 1907. Serial No. 398,?59.

To ab. lwhom it may confiera:

le it known that l, FRANK R'. CUNNING- nnn, of Medford, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Tweezers, of which the following is a specification.

The object of the present invention is to' provide tweezers which will cl'ose automatically to grip small articles, and are so shaped as to be capable of pickingl up and holdingl such articles so that they can be measured and placed accurately in whatever position it may be desired to locate them.

The invention consists in' an instrument of which the preferred embodiment is illustrated in the accompanying drawings and described in the following specification.

l `igure l represents an elevat-ion of the' tweezers. F ig. 2 represents an axial section on an enlarged scale, showing the parts in normal position with the jaws closed. Fig. 3' represents a view similar to Fig. 2, of the lower part of the instrument, showing the z jaws open. Fig. 4 represents a perspective view of the jaws detached. Fig. 5 re resents' a similar view of the plunger from w iich the jaws are hung. Fig. 6 represents' a Sectional view of the lower end of the shank or barrel of the instrument. Fig. 7 representsan elevation of the lower part of the instrument,- illustrating the manner of its use.

The same reference characters indicate the same parts in all the figures.

Referring to the drawingstheI main por'- tion of the instrument consists of a tubular j shank or barrel 1 in the central `bore of which is contained a plunger or bar 2 from which the tweezer jaws 3 4 are hung. These jaws are preferably made from a-single piece of resilient metal and are therefore connected together by an integral neck 5. Being cut from one piece of sheet steel or any other suitable metal, the jaws are separated by the removal of a cent-ral tongue which leaves a long slot 6 between them. Near the connecting nec-k the jaws are narrowed so as to form resilient Shanks which allow the jaws to be pressed together by the application of suiiicient force, and normally hold them separated when the pressing force is released.

0n the upper end of the plunger or bar is a. threaded stem 7 upon which is screwed a sleeve 8 projecting from the top of the tubular body. A spring 9 surrozmf-iug the stein bears against a shoulder 10 and against the bottom of the sleeve 8, tending to raise the plunger andtweezer jaws and press the beveled outer edges 11 of these jaws against the walls of shallow, inclinedl int?, 11a cui; in the lower end of the barrel l. YV hen these inclined edges are brought. against the walls o-f the slots or against the lower rim of the barrel, they act as cams and draw the ends of the jaws together, as shown in Fig. 2. The spring 9 is strong enough to overcome the friction of these cam edgesy and the spring of the jaws, so that the normal position when the parts are in equilibril'un is that illustrated in Fig. 2. The jaws are inserted into a jaw 12 in the lower end of the plunger and hang freely from a pin 13 which crosses such slot so that they bear with eqpzl force against both sides of the barre A button 14 surrounding the upper end of the sleeve 8 and bearing against shoulderl, being held thereon by a set-screw 16, serves as a finger piece by which pressure may be applied to lower the plunger' 2 and allow the jaws to free themselves and spring apart. Upon this pressure being removed, the Spring 9 returns the parts and causes the jaws' to approach one another. This result is of importance, since itv causes articles gripped by the tweezers toA be held without any exertion on the part, of the user, and so eliminates any danger of tiny articles being lost by relaxation of .the grip of the user, due to fatigue, such as would be the case if the jaws were normally held open and were closed only by muscular effort.

A particular use for which this instrumentis designedV is the handling of jewels and other small parts of watches, and more especia-liv for picking up and placing roller jewels and small stones and metallic pins.

To permit small pin-shaped articles to be picked up from an extended surface and securely held so that they can be .measured and then inserted into a place designed for them, the outer ends of the tweezer jaws are inclined at a considerable angle to the main portion of the jaws, and to the axis of the instrument. Thus the inclined portions of the jaws may be laid flat on a fiat surface, while the axis of the tool itself is at a considerable angle above the same, as illustrated in Fig. 7. Furthermore, on 4the inner sides of the jaws are .formed longitudinalslots 17 extending inward from the ends ofthe jaws to the angle where the inclined ends join the main portions of the jaws. hese slots are located so near the lower or outer surfaces of the jaws as to be separated therefrom by edges 18 which are scfne and sharp as to have no appreciable superficial area.` This location of' the slots,'as well` as the angle which they makg with the axis of the tool, allows articles shaped similarly to the roller jewel 19 shown in Fig. 7, to be picked up from a fiat surface, accurately positioned and firmly held. By reason of the sharpness of the edges 18, the pin will be sure to enter the grooves 17 and to lie longitudinally therein. From this location it cannot fall out or be easily displaced'except upon separation of the jaws, and so can be meas-v ured by calipers and can then be set in place.

One use to which this tool is particularly adapted is for fitting or trying the roller jewel of an escapement in the forkiof the escape pallet of a Lwatch movement. By virtue of the fact that the ends of the jaws are bent, the roller jewel may be picked lu from a fiat surface and securely held without supplementary adjustment -of the jaws. By virtue also of the fact that the jaws are automatically and ynormally closed, theroller jewel can be held while it is inserted in the pallet fork, without the necessity of the watch-maker employing any force to grip the jaws on the jewel. This is of considerable importance, as thereby the watch. maker is enabled to hold the tool lightly and to move it back and forth to see whether there is any play of the jewel lin the pallet fork. If he were obliged to use force to hold the jaws closed in gripping relation upon the jewel, he could not have-the same delicacy of touch to determine the amount off4 fork.4 Finally, by virtue of the slender construction of the tweezer jaws the watchmaker may fit the roller jewel in the pallet fork without removing the pallet from the watch movement. When the watch movement is put together the space in which the tweezers may be passed for the purpose above-noted is exceedingly restricted, and no tool except one having substantially the di lmensions shown could be inserted therein. To the best of my knowledge this tweezei is the first tool which has ever been produced capable of use in the ,manner abovc defined, that 1s of first gripping and picking up a roller jewel and then of fitting and testing it in the fork of an escapement pallet while the pallet is in place in the assembled watch movement.

I claim j A tool comprising a tubular barrel, a plunger movable endwise therein and projecting from one end thereof, a spring arranged to act on said plunger with tendency to move the projecting end thereof outward, said plunger having a slot at its other end, which is contained within' the barrel, a pin crossing said slot, and tweezer jaws formed of one piece stamped from a metal sheet, having a slot between lthem and connected by an integral neck, hung by said neck from said pin, said jaws having exterior cam surfaces which are brought into contact with the end of the barrel by the action of said spring to close the jaws together, the jaws being further bent out of a straight line at their extreme ends, to permit of their grasping pins lying on a table, and having longitudinal c0- operating grooves to contain such pins.

' In testimony whereof I have aiiixed my signature',*iii'iprescnce of two witnesses.

l FRANK R. CUNNINGHAM.

vplay between the jewel andthe arms of PEZZETTI. 

